This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations are utilized herein:
3GPP third generation partnership project
ACK acknowledgement
BPSK binary phase-shift keying
CAZAC constant amplitude zero autocorrelation
CM cubic metric
CQI channel quality indicator
DNA data-non-associated
DL downlink (Node B to UE)
DL-SCH downlink shared channel
eNode B evolved Node B (LTE base station)
E-UTRAN evolved universal terrestrial radio access network
LTE long term evolution of UTRAN (E-UTRAN)
NACK negative acknowledgement
Node B base station
PAR peak-to-average ratio
PUCCH physical uplink control channel
PUSCH physical uplink shared channel
QPSK quadrature phase-shift keying
RACH random access channel
RAN radio access network
RRC radio resource control
RS reference signal
SF spreading factor
SR scheduling request
TSG technical specifications group
TTI transmission time interval
UE user equipment, such as a mobile station or mobile terminal
UL uplink (UE to Node B)
UTRAN universal terrestrial radio access network
VoIP voice over internet protocol
WG working group
The 3GPP has been working on the standardization of LTE (E-UTRAN). In the absence of UL data, data-non-associated control signals (e.g., ACK/NACK, periodic CQI) are transmitted on the PUCCH. Furthermore, it has been decided that:
(a) ACK/NACK (only) signals are transmitted utilizing modulated CAZAC1 sequences (coherent): BPSK is used for 1-bit ACK/NACK and QPSK for 2-bit ACK/NACK. Block-wise spreading with SF=3/SF=4 (pilot/data) is applied for the modulated CAZAC sequences. 1 The applied sequences may not be true CAZAC but computer searched Zero-Autocorrelation (ZAC) sequences. The same sequences are applied as reference signals with bandwidth allocation of one resource block.(b) Periodic CQI (and combinations of CQI and ACK/NACK) is also transmitted utilizing modulated CAZAC sequences. Block-spreading is not used.
In the 3GPP TSG RAN WG1 meeting #47bis in Sorrento, it was agreed that a non-contention based SR mechanism for time synchronized users will be supported.
The basic principles for SR multiplexing were agreed to in the 3GPP TSG RAN WG1 meeting #50bis in Shanghai. Reference in this regard may further be made to R2-074333, 3GPP TSG-RAN WG2#59bis, Alcatel-Lucent, “Handling NAS messages during HO,” Oct. 8-12, 2007, Shanghai, China.
In the Shanghai meeting, the following was also decided:
(i) There are two sizes of the SR corresponding to two states. Either the UE requests to be scheduled or (in case of no transmission) the UE does not request to be scheduled.
(ii) On-off keying based on ACK/NACK design: The length 7 sequence is split into two orthogonal sequences of length 3 and length 4. FIG. 1 shows the length 7 sequence 40 with two constituent orthogonal sequences 42, 44 of lengths 3 and 4, respectively.
(iii) There will be compatibility with ACK/NACK transmissions from different UEs.
(iv) Different resources corresponding to a cyclic shift and an orthogonal cover code can be assigned for scheduling requests and ACK/NACK.
It is noted that the ACK/NACK signaled on the UL is related to DL-SCH (Physical Downlink Shared Channel, PDSCH). In the case where the UE has no data to transmit (i.e., on the UL), the ACK/NACK is signaled on the PUCCH. When the UE has UL data to transmit, the ACK/NACK is signaled on the PUSCH.